1. Field of the Invention
This invention relates to an extruded sealing section with a U-shaped transversal section, made of elastomer or plastomer, without a rigid reinforcement such as, notably, a metallic reinforcement. More specifically, it concerns a clamp-forming section of this type, designed to be mounted onto a projecting part of a structure, especially an edge projecting from the frame on an opening in the body of a car, particularly a door frame or trunk frame on such a body.
In addition, the invention involves a blank or pre-form for such a sealing section and a procedure for mounting said blank onto the projecting part of the associated structure in order to create the section and simultaneously make it integral with this part.
The clamp-forming U-shaped sections typically include at least one sealing component adjacent to the base or to a branch of the U shape and projecting toward the outside in such a way that it is compressed between the frame of the opening fitted with this section and the relevant panel, door or lid when the latter is in a closed position, thereby ensuring that this opening is waterproof and soundproof. To ensure that these sections are effectively clamped onto the flange on which they are mounted, they have traditionally included a U-shaped metallic reinforcement at least partially buried in the plastomer or elastomer of which they are made, and, to ensure that the section is not inadvertently disconnected from the associated flange, each wing of the section corresponding to the branches of the U shape usually includes lips or gripping fins that project obliquely in the direction of the other wing from the surface turned toward that wing.
With the same objective, the users of these sections, particularly when the sections have no metallic reinforcement, ensure that they are securely in place by gluing them to the flanges onto which they are fitted, and, for this purpose, they typically use so-called hot-melt glues, which are hard at room temperature but soften when heated. Consequently, users must coat the internal surface of the section base and/or the adjacent parts of the wings with this type of glue on the spot in the presence of heat and then, after the assembly has been heated in order to soften the adhesive and allow it to flow between the section and the flange, they must mount the section to which glue has been applied onto the flange; finally, they must allow the assembly to cool in order to harden the adhesive and thereby secure the section onto the flange.
These steps are relatively simple; nonetheless, users object to the need to heat the adhesive themselves and bemoan the lack of sections that can be mounted directly onto the associated flanges, without having to resort to this tedious operation beforehand.
2. Description of Related Art
From Patent FR 2 633 361 A, we are familiar with a seal made of a flexible extruded material and having a transversal section generally in the shape of a U or a Ω, at the bottom of which is implanted an adhesive substance, such as a mastic. This section is designed to be mounted onto a flange or a projecting edge that penetrates into the adhesive substance, which then hardens naturally, so that the section adheres to the flange or the projecting edge, but this may require a considerable period of time.
To remedy this drawback, it has already been proposed to apply a line of soft glue inside the clamp-forming section that can be hardened by a controlled operation, e.g., heating by means of an electrical conductor buried in the mass of the section or in the line of glue (see EP 1 060 927 A and EP 1 080 967 A, both of which belong to the Applicant). With sections such as these, the projecting part is mounted so as to penetrate the line of soft glue, and this glue is subsequently hardened.